Reducing 3-pentanone with hydrogen in the presence of a nickel catalyst yields 3-pentanol. This reaction is an example of a hydrogenation reaction, in which a hydrogen molecule is added to an alkene or an alkyne molecule in the presence of a catalyst. The catalyst helps break the hydrogen molecule into two hydrogen atoms, which can then attach to the double bond of the alkene or alkyne.

The reactants for the hydrogenation reaction of 3-pentanone are hydrogen and 3-pentanone, with the nickel catalyst included. 3-pentanone is an oxo ketone, with a carbonyl group (C=O) and a hydroxy group (OH) connected to a five-membered carbon ring. The hydrogen is added specifically to the carbon-oxygen double bond, resulting in the formation of an alcohol. The alcohol produced by the reaction is 3-pentanol, which comprises a five-membered carbon ring with a hydroxy group and two alkyl (CH3) groups attached.

The hydrogenation reaction involving 3-pentanone requires a catalyst, which in this reaction is a nickel catalyst. Nickel catalysts are part of the class of catalysts known as transition metal catalysts, which are able to catalyze a variety of different reactions. Transition metal catalysts are also able to increase the rate of the reaction, allowing it to take place at lower temperatures or shorter times. In the case of the hydrogenation reaction involving 3-pentanone, the nickel catalyst is able to facilitate the breaking of the hydrogen molecule into two hydrogen atoms, which can then attach to the double bond of the 3-pentanone.

The hydrogenation reaction involving 3-pentanone and a nickel catalyst yields 3-pentanol. This reaction is an example of a hydrogenation reaction, in which a hydrogen molecule is added to an alkene or an alkyne molecule in the presence of a catalyst. The catalyst helps break the hydrogen molecule into two hydrogen atoms, which can then attach to the double bond of the alkene or alkyne. This yields the desired alcohol, in this case 3-pentanol, which is made up of a five-membered carbon ring with a hydroxy group and two alkyl (CH3) groups attached.